4000 rev cut out

Alternator, waterpump, A/C, sensors, CAS, etc.

Moderators: theelanman, dapinky, Specky, Dave Eds, DaveT, Elanlover, Nige, muley, Enright, Sy V, algirdas, nitroman, clemo, GeoffSmith

4000 rev cut out

Postby Dave Thomas » Thu 16.04.2020, 19:46

I have looked at the various posts on this common problem and the consensus seems that the commonest cause is boost overpressure. On the paper clip OBD trick I get repeated 1:2 flashes and nothing else on the engine warning light. I have tweaked the actuator rod on the wastgate, and connected a pump to the wastage controller and it opens easily and freely below 9psi, which I assume means the diaphragm is OK. The engine still cuts out around 4000rpm but runs well before this. The dash boost gauge seems to work and seems not to go above 0.5 bar before it cuts.
Looking at the exhaust it is an aftermarket stainless ? performance exhaust. The previous owner's documents show that he bought the exhaust in 2011 from Cybrand, Chester (now out of business) and the part number was SFS/441/H1, which though I can't find it, is probably a performance item.
The relevant Forum here suggests that the wastage should be ported to compensate for the effect of the lower exhaust resistance / pressure.
Is there anything else I should try before wrecking my knuckles or paying a specialist to do it properly?
BW
Dave Thomas (Newbie)
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby GeoffSmith » Thu 16.04.2020, 19:55

I think everyone who bought a Peco (now Cybox) exhaust ended up having to port the wastegate Dave.
Calypso Red S2 #417

USB ElanScan interfaces - £60 incl. P&P.
User avatar
GeoffSmith
Kitty Fiddler
 
Posts: 15048
Joined: Fri 03.02.2006, 21:57
Location: S2#417 in Tytherington, Gloucestershire

Re: 4000 rev cut out

Postby Rambo » Thu 16.04.2020, 21:16

Not me Geoff. I had one of the very 1st PECO development exhausts (along with you and Monty) and never had to port Red Rambo's wastegate, despite a heavy right foot :burnout:
User avatar
Rambo
Don't push me
 
Posts: 7647
Joined: Wed 24.12.2003, 00:37
Location: Kelso

Re: 4000 rev cut out

Postby Simon_P » Fri 17.04.2020, 04:07

Hi Dave and welcome to LEC.

It might help to clarify a few things.
4000 rpm is a rev limit set by the ECU in response to several faults - if the limit is set the CEL should be on and a fault code set overboost is 31.
You get code 12 three times before you get the fault code.
The boost gage is independent of engine management and is showing actual manifold pressure if you have overboost it should show it.
Overboost can happen across the rev range the response is a fuel cut.

What you describe doesn't sound like overboost.

Two things that will cause a missfire but not set a code are injectors and HT I would look towards coil packs.
Simon_P
God
 
Posts: 1560
Joined: Fri 06.08.2004, 12:33
Location: Kent UK

Re: 4000 rev cut out

Postby Dave Thomas » Fri 17.04.2020, 16:16

Thank you all for such prompt replies. I reckon its a feature of lockdown. I get the 1:2 warning light code about a dozen times in succession and gave up waiting for anything else to appear!
The ignition coils / plugs fix would be a relative dream compared to a turbo fix I guess but it does not misfire until reaching around 4000 revs. Is it still possible that that could be the problem?
BW
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby dapinky » Fri 17.04.2020, 17:37

A missfire at specific revs could easilly injdicate a fault in either the HT leads, Coil Packs, Injectors or electric impulses to operate any of those.... Because of the locationof these things, they tend to breakdown at a certain temperature/operating condition. A slight flaw in a sparkplug cable may still pass enough current at lower revs, but once it gets to a higher requirement, it heats up and can't cope.

Can we clarify if it is a 'missfire' at 4000+ revs (whereby it runs inconsistantly at higher speeds), an inability to exceed 4000 revs, or a definative 'cut' at 4000 revs (symptoms like hitting the brakes hard).

Each of these 3 things (coupled with a lack of CEL/Paperclip code) will have a different approach to isolating the problem and - hopefully - solving it.
Dave

Just the one now, but this one's mine! - and it will be finished eventually.....

go on - click this link - you know you want to!
User avatar
dapinky
LEC Administrator
 
Posts: 8713
Joined: Sun 15.10.2006, 12:54
Location: As far west as you can get in West Wales before you become Irish (Pembroke Dock).

Re: 4000 rev cut out

Postby Rice crispy » Fri 17.04.2020, 18:12

I had a coil start to break down at higher revs would idle fine and drive around fine till I accelerated harder then it would start to stutter. Changed both coils and leads as a precaution.
Last edited by Rice crispy on Sun 19.04.2020, 19:56, edited 1 time in total.
User avatar
Rice crispy
God
 
Posts: 1827
Joined: Tue 16.06.2009, 11:48
Location: brentwood essex

Re: 4000 rev cut out

Postby Dave Thomas » Sun 19.04.2020, 11:26

Thanks all
It seems like the brick wall described in the postings at 4000 revs. So I had assumed the cut out option. I hope to have the connection for the OBD1 coming soon and this may give me more info.
I wonder if elanscan will clarify the issue.
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby Portugal_lotus » Mon 20.04.2020, 00:53

Hi Dave ,
Check this post
viewtopic.php?f=37&t=26686
Portugal_lotus
Newbie
 
Posts: 42
Joined: Sat 17.01.2004, 02:30

Re: 4000 rev cut out

Postby Dave Thomas » Mon 11.05.2020, 15:00

Hi all
I am posting a PDF file with the elanscan data. The wastegate duty cycle, which may not be included just reads 0 throughout.
The guy before me had installed a manual wastegate controller which I have disconnected but I am guessing he would have had to inactivate the BCFV, although this appears connected electrically, and with the hoses. The wastegate actuator moves on wiggling and if pressurised by a pump but does not appear to operate when the engine is running.
Any suggestions?
Thanks in anticipation
Dave
Attachments
DT Elanscan.pdf
(442.91 KiB) Downloaded 16 times
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby Fredjohn » Mon 11.05.2020, 19:18

Dave

Did you do this test on a driveway or by driving on the road for a few miles? I'm guessing on the drive as it's only 2mins of data.

The turbo does not operate a) until a certain temp has been reach AND b) unless you are driving, not just revving when stationary.

You will have to go for a 20-30 minute drive to get a decent data set.

Are you still having trouble zipping the ecu file? If you can manage, there will be far more data than just engine speed.
La vie passe vite: vivez la avec elan(s).

Elan S4 DHC 1969
Elan SE turbo 1992
Evora 2010
MB CLK 320CDi 2007
Boardman Endurance SLR 9.4 disc carbon road bike
Swift Sundance Lifestyle 500
User avatar
Fredjohn
God
 
Posts: 1872
Joined: Tue 21.08.2012, 00:30
Location: Malvern, Worcs

Re: 4000 rev cut out

Postby Dave Thomas » Mon 11.05.2020, 20:14

Thank you. I did a second scan with the engine up to temp (including fan working) which looked the same but still on the drive. I have had an issue with using an old PC with a duff battery which I have connected to the mains. Will find another with a working battery and venture out soon.
BW
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby rip » Tue 12.05.2020, 21:44

Mine readily cut out at 4000rpm & even though the boost gauge was reading around 0.6bar, I felt very little extra power from the turbo.
It burbled like crazy when I took my foot off the accelerator & someone called Geoff said "popping = poor timing".
Timing seemed to be fine at 16btdc, so I discarded the timing light & did some test runs, adjusting the timing each time. I found that 32btdc gave best performance before any knock was recorded on Elanscan.

Surely my timing mark must be out but how? It is is a pathetic little mark so maybe something else looked more like the real mark?
Performance was like night & day. The turbo put a smile on my face again, it revs well past 4000rpm & only ever hit overboost in cold weather & no more overrun popping.
1990 SE
User avatar
rip
God
 
Posts: 5818
Joined: Sun 08.04.2007, 07:48
Location: Milton Keynes, UK

Re: 4000 rev cut out

Postby lotusrepair » Wed 13.05.2020, 05:47

I posted some time back of this type of thing happening to me. On a acceleration from time to time the engine would stumble at about 4k rpm. I changed the coil packs and controller and though it went away but the problem was still there. It happens only now and then. Nothing to make it repeat the same fault each time. I have pnm exhaust for comparing to the other cars with same issue. I had a idea that this might be linked to the throttle position sensor. There is a limit on boost at low rpm and then it changes after the revs pass the limit point. That point is 3900 rpm. I have no trouble codes.

Chris
User avatar
lotusrepair
Enthusiast
 
Posts: 185
Joined: Sat 27.12.2014, 01:58
Location: Maryland, USA

Re: 4000 rev cut out

Postby Dave Thomas » Wed 20.05.2020, 17:33

I have finally sorted 30 minutes of data re the 4000 cut out (still doing it). Would value any advice. Could be an issue related to the sports exhaust as Geoff has suggested. Have had a squint at it and it seems similar to the 'on the drive' one. Wondering why the temperature is -39 continuously and the registered temp on the guage seems to stay at 1/4 of the way up.
Dave
Attachments
elanscandataDT5.zip
(186.62 KiB) Downloaded 8 times
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby rip » Thu 21.05.2020, 07:07

Dave Thomas wrote:Wondering why the temperature is -39 continuously and the registered temp on the guage seems to stay at 1/4 of the way up.


I think you have found the fault yourself, or at least a fault which needs correcting before you can do anything else.

The ECU works from a single temp sender, but a different one from the dash gauge. If its sensor is telling it -39 then it will be fuelling for those conditions. I would expect it to cut out shortly after a cold start & will not boost over 4000rpm because its only sensor is telling it the engine is cold.
It will only show error if a sensor goes outside a pre-programmed range. In the case of the temp sender, I believe this is around -40c.
It has no second sensor with which to sanity check this reading. IIRC, the sensor is on top of the inlet manifold.
Either the sensor is faulty or a wire is broken.
1990 SE
User avatar
rip
God
 
Posts: 5818
Joined: Sun 08.04.2007, 07:48
Location: Milton Keynes, UK

Re: 4000 rev cut out

Postby Dave Thomas » Thu 21.05.2020, 15:03

Thank you for that expert diagnosis. Will investigate/ replace temp sensor and try again.
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby Dave Thomas » Thu 21.05.2020, 16:02

With ignition on the wiring delivers 12V, though somewhere it says the engine management should deliver 5V - ? maybe when running. Have ordered a replacement anyway as its £19.
Heres hoping.
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby Dave Thomas » Thu 28.05.2020, 12:17

PS the 12V was for the coolant temp sender operating the fans. The proper CTS is getting 5V. Awaiting the new one, fingers crossed. It is pretty inaccessible even after moving the oil separater hose and the plug leads. Might have to remove more stuff.
BW
Dave
Dave Thomas
Newbie
 
Posts: 24
Joined: Fri 10.04.2020, 17:11
Location: Sutton Coldfield, West Midlands

Re: 4000 rev cut out

Postby GeoffSmith » Thu 28.05.2020, 14:09

Calypso Red S2 #417

USB ElanScan interfaces - £60 incl. P&P.
User avatar
GeoffSmith
Kitty Fiddler
 
Posts: 15048
Joined: Fri 03.02.2006, 21:57
Location: S2#417 in Tytherington, Gloucestershire

Next

Return to Engine Ancillaries

Who is online

Users browsing this forum: No registered users and 1 guest